Fire resistant materials

Abstract

A method for forming a fire resistant material is disclosed. The method comprises providing a plurality of expandable beads of a polymeric material. The beads are coated with an exfoliable graphite. The exfoliable graphite is adhered to the beads with a resin having a solubility parameter of the polymeric material. The beads are thereafter caused or allowed expand and fuse.

What is claimed is: 
     
       1. A composition for forming a fire resistant material comprising a plurality of expandable beads of a polymeric material, wherein the polymeric material comprises polystyrene, said beads being coated with an exfoliable graphite, wherein the exfoliable graphite is adhered to the beads with a resin comprising an emulsion comprising one or more of vinylidene vinyl chloride copolymer and methylphenyl siloxane, the resin having a solubility parameter of within substantially 0.5 (cal. cm −3 ) −1/2  of the solubility parameter of the polymeric material. 
     
     
       2. A composition according to  claim 1 , wherein the resin comprises an emulsion further comprising one or more of a styrene/acrylic copolymer and a styrene homopolymer. 
     
     
       3. A composition according to  claim 1 , wherein the resin includes a halogenated flame retardant. 
     
     
       4. A composition according to  claim 3 , wherein the resin includes a synergist comprising an oxide of an element of Group 6B of the Periodic Table. 
     
     
       5. A composition according to  claim 3 , wherein the halogenated flame retardant comprises a brominated flame retardant. 
     
     
       6. A composition according to  claim 3 , wherein the flame retardant comprises hexabromocyclododecane. 
     
     
       7. A composition according to  claim 4 , wherein the synergist comprises tungsten oxide. 
     
     
       8. A composition according to  claim 4 , wherein the synergist comprises yellow tungsten oxide. 
     
     
       9. A composition according to  claim 1 , wherein the expandable beads comprise partially expanded polystyrene beads. 
     
     
       10. A fire resistant material comprising a composition according to  claim 1  wherein the beads have been allowed to expand and fuse together. 
     
     
       11. A method of forming a fire resistant material comprising:
 providing partially expanded polysterene beads; 
 coating the partially expanded polysterene beads with exfoliable graphite using, as an adhesive a resin comprising an emulsion comprising one or more of vinylidene vinyl chloride copolymer and methylphenyl siloxane, the resin having a solubility parameter of within substantially 0.5 (cal. cm −3 ) −1/2  of the solubility parameter of the polystyrene beads; and 
 forming the coated partially expanded polystyrene beads into blocks by a final expansion in closed form using steam. 
 
     
     
       12. A fire carrier formed of a fire resistant material according to  claim 11  arranged between non-flammable outer skins where the fire resistant material contains sufficient exfoliable graphite substantially to fill a cavity between the skins on expansion thereof after melting and loss of within substantially 0.5 (cal. cm −3 ) −1/2  of the polymeric material in a fire situation.